and a whole bunch of similar satements to remove all keyboard characters from a textfield, except the digits.... - (the minus sign), + (the plus sign), as well as 0,1,2,3,4,5,6,7,8, and 9 numbers in a text field. The example above simply converts a comma in an NSString to a null value.

Hate to admit it, but in one project, I'm actually using about 80 statements -- one for every keyboard character except those shown above. Thee must be some easier way. What would you suggest to do this job?